The present invention relates generally to golf clubs and their manufacture, and is particularly concerned with golf clubs of the so-called "metalwood" type.
Golf clubs are generally divided into four main types, comprising putters, irons, fairway clubs and drivers. Drivers in the past were normally made of wood, and so were often referred to as "woods". More recently, drivers have been made of metal and so are often now called metalwoods.
Most metalwoods are conventionally made of stainless steel, and with very few exceptions they are manufactured by investment casting a hollow stainless steel shell. The investment cast process can be inconsistent, and the golf club has a face which can be inconsistent and can contain sinks. It must be polished and is normally cosmetically sand blasted to hide its imperfections. When investment casting thin wall stainless steel heads, a large number of rejections result due to porosity and thin spots. The investment casting process itself is expensive, involving high tooling expenses, and the results are inconsistent.
Stainless steel is relatively heavy and thus the walls of the club head must be made relatively thin in order to maintain an acceptable club head weight. Since the skin is relatively thin, relatively high amounts of club face deflection occur when the club head strikes the ball, resulting in inconsistent performance.